Labyrinth packing for rotary machines.



PATENTED NOV. 13, 1906. R. SOHULZ. LABYRINT'H PACKING FOR ROTARY MACHINES. APPLICATION FILED FEB. 27, 1906.

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PATENTED Nov. 13, 1906. r

2 sums-sum 2" R. SOHULZ. LABYIRINTH PACKING FOR ROTARY MACHINES.

APPLICATION FILED T15R27, 1906.

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UNITED STATES PATENT OFFICE.

RICHARD SCHULZ, OF BERLIN,.GERMANY. LAB YFIINTH PACKING, FOR ROTARY MACHINES- Specification of Letters Patent.

Patented Nov. 13, 1906.

Application filrl February 2'7, 1906. Serial No. 303.205-

To all whom it may concern:

Be it known that I, RIcHARi) Sc-HULz, a, subject of the King of Prussia, German Emperor, residing at Flensburgerstrasse 2, Berlin, Germany, have invented certain new and useful Improvements in Labyrinth Packing for Rotary Machines; and I do hereby declare the following to be full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters of reference marked thereon, which form a part of this specification.

Labyrinth packing for rotary machines is, as is well known, employed in steam-turbines in various places at which the escape of the steam from a space inside the steam-turbine to an adjacent one inside or outside the same is to be prevented. The essential feature of such labyrinth packing consists in its being formed of annular ribs formed on the shaft or other part of the machine by annular grooves being turned therein, in combination with annular ribs on the part (casing or the like) of the machine which surrounds the shaft or the like, the ribs alternating with and engaging over one another. Forinstance,alabyrinth packing is employed at the place at which the shaft emerges from the casing of the steamturbines in impulse steam-turbines, also between the separate tiers of the same along the shaft, in which case the labyrinth packing is of comparatively small diameter. Labyrinth packing of larger diameter is employed in reaction steam-turl. ines at the so-called balance-piston. Here, in the one case, the diameter is about equal to the smallest mean diameter of the reaction-turbine, in the other case about equal to the greatest mean diameter of the same.

In order to obtain a suitably-tight joint with annular ribs or ridges, a large number of them must be provided. In order that they may not bend under any circumstanccsfor instance, in transport or by any contact with one another by reason of inexact adj ustmentthe annular ribs must have a certain minimum thickness. For this reason the introduction of such a packing requ ircs additional space in the direction of the length of the steam-turbine. It is of importance to reduce this to a minimum in all steamturbines, and especially those for ships, because the shorter a steam-turbine is and the smaller the distance apart of its shaft-bearings the less strength is required for the separate part-s of the same and the more advantageously the turbine-wheels aresupported. This invention has for its object to render the arrangement just foreshadowed possible. The improved labyrinth packing for rotary parts of machinery is for this object provided with annular ribs or ridges, formed by turning annular grooves, which ridges in section increase in thickness from the crown to the base-that is to say, are wedge-shaped in section. A labyrinth packing with such annular ribs complies with the requirement as regards strength better than the ordinary ones and affords the most effective surfaces with the smallest requirement of space.

In the accompanying drawings, Figures 1 and 2 are known labyrinth packings of this kind in longitudinal section. Figs. 1, 2, 3, 4, 5, and 6 are some examples of construction of the improved labyrinth packing; and Figs. 7, 8, and 9 are sections of the respective parts of steam-turbines, showing'ways in which the packing is employed.

All the figures show the labyrinth packing adjusted for the Working turbine. In this condition, between the annular ribs (1 of the rotor (turbine-shaft and turbine-body) and the annular ribs b, fixed on or in the casing, there is formed on the one side of the ribs a very narrow and on the other side a comparativcly wide passage.

In the labyrinth packing hitherto constructed of the kind in question the annular ribs or ridges have generally a rectangular section, as shown inFig. 1*; In the form of construction also employed, such as is shown in Fig. 2, the annular ribs on one side are undercut at the base, and farther on the other side of the ribs an excessively-wide interval is provided. With this form of construction a minimum total length of the packing is even less attainable than with the first-mentioned form of construction.

In order to obtain the most effective packing-surfaces of the annular ribs with the greatest saving of space, a wedge-shaped cross-section is given to the annular ribs in i such a way that the thickness of the rib gradually increases from the crown to the base of the ribs.

The wedge-shaped annular grooves cut in the respective parls (shaft and turbine body action, suitably-proiiled grooves i, as shownin Figs. 3 and. t, may be turned in the feces of the annular ribs, which form with one another the narrow interval. 'ihese grooves "i form hollow spaces or pockets in which solid or lluid particles may be deposited and pro-- cipitated and hove the further advantage that in case the annular ribs encounter one another, owing to inexact edjustment, they do not sufl'cr so much and are not so much worn.

A comparison with the known labryinth packing or joint, such as shown in Fig. 1, yields the following: With six annular ribs which engage oversix other ribs-that is to say, with siX narroi intervals, es in the form of construction shown in Figs. 1 and 2, this improved labyrinth pecking has with an equal height of the ribs a total length which only amounts to twothirds of the total length of the ordinary form of construction, such as shown in Fig. 1*. in the form of construction shown in Figs, 3 and l the total length of the packing with four annular ribs which'engcge over four othcrstlnit is to say, With four narrow intervals and with one and one-half times greater height of ribs --is not half the total length of the ordinary form of construction shown in Fig. -1. With a still more pointed Wedge the Wcdge-slniped annular ribs may have even a greater height than the ordinary annular ribs of rectangular section, as the former are much more re sistent to bending, even when highly heated. lhe annular ribs do not necessarily require to be made in one piece, as shown in Figs. 1-4, with the rotury port (shaft or the like) of the machine and the fixed pert, (casing) The labyrinth packing might, for instance, as shown in Fig. 5, be made of separate rin s c I), lying closely side by side and he d firmly together.

As further shown in Fig. 6, separate rings or ring-segments c b may also be firmly inserted in minuhur grooves of the respective parts, and then they fulfil the some object. The rings or ring-segments may be held fast in the ordinary woy by haunnering them lightly down in the annular grooves of the main body of the rotary and fixed parts.

Fig. 7 shows an example of the use of the labyrinth packing hercinbeforc described for an impulse steam-turbine with axial flow. Both the rotary. turbine-midy and ulso the turbine-shalt engage, by means of annular ribs 0;, which are wedge-sha ed in section, with corresponding annular ribs 1) in the easms access ing. In a. redieldiow turbine, combined With on aXiaHlow turbine, as shown in Fi 8, an nular ribs c, which are wedge-shape in section, engage over suitably-proliled annular ribs 1), which are mounted in the turbine casw ing.. The some applies to the example of construction shown in Fig. 9, in which the annular ribs (1 and b engage over one another in an axial direction instead of in a radial direi'liou, as in the other examples.

From, the examples hereinhefore mentionod the great value of the labyrinth coking hereiubefore described may be got lercd more particularly by reason of the circumstance that they occupy the minimum of space.

I declare that what I claim is* 1. A labyrinth packing comprising spaced annular ribs on the rotating element and similar spaced ribs on the'stationary element fitting between the ribs on the rotating element, said ribs Wedge-shaped in cross section from their root to their crown and positioned to provide a wider interval on one side of a rib than on the other, said Wider interval less than the thickness of a rib, substantially as and for the purpose set forth.

2. A. lab rinth packing comprising spaced annular, ri s on the rotating element and similar spaced ribs on the stationary element fitting in the spaces between the ribs on the rotetm element, said ribs having one face per-pen icular to the element on which they are mounted and the other face inclined from the root to the crown and positioned relativel to one another to forms wider passage between the inclined faces thanbetween the perpendicular faces, substantially as and for the purpose set forth.

3. A lab rinth packing comprising spaced annular rii is on the rotating element and similar spaced ribs on the stationary element fitting-between; the ribs on the rotating element, said ribs Wedge-shaped in section from their root to their crown, and concentric grooves cut in the faces of the ribs on one of the elements substantially as and for the purposes set to 'th.

4. A labyrinth packing comprising spaced annular ribs 011 the rotatin element and similar spaced ribs on the stationary element fitting between the ribs on the rotating element, said I ribs wedge-shaped in section from their root to their crown and positioned relatively to one another to form. a wider space on one side of a rib than on the other, and concentric rooves cut in th faces of the ribs adjacent t e narrower space, substantially es and for the purposes set forth.

5. A labyrinth packing comprising spaced annular ribs on the rotating element and similar spaced ribs on the stationary element lilting between the ribs on the rotating element, said ribs wedgwshaped from their root to their crown and positioned relatively to In testimony that I claim the foregoing as one another to form a wider space on one 1 my invention Ihave signed m'y'name in presside of a rib than on the other, the faces of l enoe of two subscribing Witnesses.

the ribs adjacent the narrow space having RICHARD SCHU LZ 5 concentric registering grooves cut therein, Witnesses:

substantially as and for the purposes set JOHANNES HIN,

forth. VVOLDEMAR HAUPT. 

